Although the anesthetic gases, halothane and enflurane, reduce the percent incorporation of 13C-label into GABA in globus pallidus, caudate, accumbens and substantia nigra, the turnover rate of GABA was significantly reduced by both anesthetics only in accumbens and by enflurane in septum. The reduced turnover rate of GABA in septum following enflurane administration may be related to the excitatory activity produced by this compound.